Integrated circuits (ICs) and other electronic apparatus often include arrangements of interconnected field effect transistor (FET) devices, also called metal-oxide-semiconductor field effect transistors (MOSFETs), or simply MOS transistors or devices. A control voltage applied to a gate electrode of the FET device controls the flow of current through a controllable conductive channel between source and drain electrodes.
Power transistor devices are designed to be tolerant of the high currents and voltages that are present in power applications such as motion control, air bag deployment, and automotive fuel injector drivers. One type of power transistor is a laterally diffused metal-oxide-semiconductor (LDMOS) transistor. Power transistor devices may have a number of features customized to prevent breakdown resulting from the high electric fields arising from such high voltages.
Power transistor devices are often combined in ICs with low voltage FET transistor devices. The low voltage devices provide logic or analog functionality to support the operation of the high voltage devices. The fabrication process flow is thus configured with a considerable number of steps directed to creating features specific to the high voltage FET devices and the low voltage FET devices. The steps may be highly customized to optimize the features of the high and low voltage devices.